Differential settlement control method

Abstract

This invention provides a construction method using steel pipes to control differential settlement of a house 1. [Solution] Within the site of an existing house 1, steel pipes are driven in according to the surrounding environment, such as adjacent houses, buildings, and structures.

Description

Technical Field

[0001] It relates to a technology for controlling and correcting differential settlement caused by the ever-changing surrounding environment of a house, earthquakes, insufficient ground support force, consolidation settlement, and traffic vibration.

[0002] Although the differential settlement of a house is caused by various factors, as a method for correcting, that is, repairing differential settlement, a method is adopted in which about 1 m is dug under the foundation, jacks are set at 20 to 30 locations, and short steel pipes are added and pressed in up to the supporting ground, and then they are jacked up simultaneously to be repaired horizontally, so as not to cause continuous settlement.

[0003] Although this method is common, it is too large-scale a construction, with a long construction period and high costs associated therewith. Therefore, there are many problems in correcting the differential settlement of existing houses, and there is a need for a new technology that can be used not only for countermeasures taken after differential settlement occurs but also for newly constructed houses.

Background Art

[0004] According to the invention described in Patent Document 1, by providing a RC continuous wall reaching the hard ground surrounding the building on soft ground and a projecting member supporting the outer peripheral portion of the bottom surface of the building, when an earthquake occurs, the water pressure in the soft ground surrounded by the RC continuous wall rises and liquefaction occurs. In the liquefied soft ground, the total buoyancy acts on the building and the projecting member, so that differential settlement of the building can be prevented.

[0005] Further, this invention describes an effect that the ground is liquefied to exhibit a seismic isolation effect, and even if the ground is liquefied, settlement and inclination of the structure can be prevented.

[0006] However, the invention according to this Patent Document 1 has a problem that it is not suitable for detached houses because construction of a RC continuous wall is required and the construction is very large-scale.

[0007] Next, according to the invention of "Foundation structure for preventing differential settlement of buildings and method for correcting differential settlement" in Patent Document 2, a concrete base slab with a U-shaped cross-section is provided in a foundation embedding recess excavated in the ground, and a part of the strip foundation is embedded in a layer of sand within the base slab. If differential settlement occurs, the sand around the less settled part of the foundation is stirred and fluidized with a vibrator 7 to cause that part of the foundation to settle, thereby correcting the settlement.

[0008] However, even in the case of this invention, the structure is large-scale, and in the case of a slab foundation, an even larger structure must be added for it to be feasible, which presents a problem. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent application 2006-314418 [Patent Document 2] Japanese Patent Application Publication No. 8-209720 [Overview of the Initiative]

[0010] The inventions described in Patent Documents 1 and 2 are neither suitable for newly built or existing houses, nor are they suitable for buildings with delicate constructions such as historical buildings; therefore, a new invention is needed. [Problems that the invention aims to solve]

[0011] The inventor therefore focused on the fact that differential settlement occurs due to loads from neighboring houses, heavy objects, and embankments adjacent to the residential building, as well as from vibrations from nearby traffic.

[0012] This phenomenon is thought to have been caused by the influence of underground stress from a house built on the adjacent property. Focusing on this, the mechanism is that underground stress is distributed downwards from the foundation at an angle of approximately 30 degrees and spreads out in a trapezoidal shape.

[0013] When neighboring houses are close together, the loads of the neighboring houses and structures overlap, creating stress concentrations. This increases the underground stress at the boundary, and if there is a weak layer beneath the topsoil, the bearing capacity decreases over time due to vibrations. The boundary with the neighboring property, where the underground stress is high, has less bearing capacity compared to other areas, causing the property to tilt towards that point.

[0014] In response to the mechanism of differential settlement, the inventor devised the first invention, a construction method to control settlement in response to differential settlement caused by earthquakes affecting the land and ground of existing houses, as well as by constantly changing surrounding environments and traffic vibrations. This method corrects differential settlement by laying steel pipes in a continuous wall-like manner on the site in the direction of settlement.

[0015] The second invention addresses the issue of differential settlement due to insufficient bearing capacity of the ground of existing houses or consolidation settlement by constructing a wall-like structure of steel pipes within the site in the direction of settlement, thereby controlling the differential settlement.

[0016] As a third invention, we discovered that the interconnected steel pipes control differential settlement by adjusting the density of the interconnected walls 11 according to the weight and distance of surrounding structures such as houses and roads.

[0017] The fourth invention is that when a continuous wall-shaped steel pipe intersects with sewer pipes, rainwater pipes, water pipes, lighting pipes, or tree roots, differential settlement can be controlled even if a gap is left in the concrete during pouring.

[0018] The fifth invention is a method for controlling differential settlement in newly constructed houses built with columnar piles, surface improvement, or no improvement, by taking into account the influence of adjacent houses, structures, and roads, and by laying steel pipes in a continuous wall-like manner in that direction within the site.

[0019] The sixth invention is a method in which differential settlement can be controlled by having a continuous wall of steel pipes reach a solid supporting layer or non-liquefiable layer in the residential ground.

[0020] Based on these, an invention was made for a construction method to control differential settlement by placing small-diameter steel pipes or the like in a continuous wall shape within the site in the direction that causes such differential settlement, without connecting them to the foundation of the house.

[0021] Also, when differential settlement is caused by consolidation settlement of clay, it takes several years to several decades depending on the properties and layer thickness of the clay until the settlement converges. However, by blocking the in-situ stress from adjacent areas with a continuous wall in the ground, the settlement on the tilted side of the house is stopped. Furthermore, it was confirmed that on the side of the house where there is less settlement on the opposite side, the settlement continues, and as a result, it gradually and automatically returns to a state of repair.

[0022] This method only requires continuous driving of small-diameter steel pipes or the like. Since it can be driven manually while adding sections, it only needs a space where people can work, and the construction cost is also low.

Effect of the Invention

[0023] The present invention can suppress differential settlement of buildings due to earthquakes and traffic vibrations by laying steel pipes in a continuous wall shape within the site of a house, regardless of whether it is a new construction or an existing building, with respect to the directions of surrounding houses and structures.

Embodiment for Carrying Out the Invention

[0024] The present invention will be described below with reference to the drawings. First, regarding FIG. 1, this cross-sectional view shows a predicted cross-section in the case of differential settlement caused by consolidation settlement of the clay layer 6 and traffic vibrations, and is a mode in which the steel pipes 4 for controlling differential settlement are placed in the site.

[0025] As shown in this figure, there is a house 1 above GL2. The ground has a clay layer 6 that continues to the support layer 13, and the house 1 is built on it. The steel pipes 4 are driven into the support layer 13 under the block wall 5 and the like within the site.

[0026] Next, let's explain Figure 2. This figure shows a configuration in which an adjacent house 10 is constructed to the east, slightly north of house 1.

[0027] Figure 3 illustrates the stresses generated from each of the houses 1 arranged in Figure 2, and shows that steel pipes 4 are driven into the site to dampen these stresses.

[0028] Next, let's explain Figure 4. This plan view shows the configuration in which buried pipes 10, such as water pipes, electrical pipes, and sewer pipes, located on the site of House 1 have been removed and steel pipes 4 have been installed.

[0029] Even in a confined space, the small-diameter steel pipes 4 can be easily driven in by hand.

[0030] Next, I will explain Figure 5. This figure shows a scenario where the houses are tilted toward the direction of the neighboring house, and illustrates the influence of stress concentration points 8 within the underground stress range 7 in the ground.

[0031] Next, let's explain Figure 6. Figure 6 is a cross-sectional view showing the settlement until it converges. Figure (1) shows the state of differential settlement at the time of pouring the steel pipe 4 into the site of the house 1 that experienced differential settlement, and Figure (2) shows the state when the control was completed.

[0032] According to this control method, instead of jacking up the subsided portion of the differentially settled house 1, the subsidence is stopped by improving the ground conditions on the subsided side with the installed continuous wall-like steel pipes 4. As a result, the side that was previously higher gradually settles, and the foundation of the house 1 becomes parallel.

[0033] This method is easy to implement and inexpensive because it only requires driving steel pipes 4 into the ground in a continuous manner. Furthermore, even if the ground is deep and solid, it can be easily added to and driven in manually, so only enough space for a person to work is needed, and it is easy to implement even in cases where differential settlement is progressing in existing houses 1.

[0034] Next, let me explain Figure 7. This figure shows the measurement of the inclination of each of the steel pipes 4 that have been driven into the ground on the site. In the case of differential settlement of the house 1, not only the house 1 is affected by the adjacent road and structure, but the ground between them is also greatly affected. By monitoring the angle of the driven steel pipes 4 with the inclinometer 12, the inclination of each of the steel pipes 4 can be obtained and used for further control.

[0035] Next, the embodiments shown in Figures 8 and 9 will be described. Figures 8 and 9 confirm that, although it takes several years depending on the properties and thickness of the clay, the continuous underground wall blocks underground stress from the adjacent house, stopping the subsidence and tilting of the leaning side of house 1. Furthermore, the side of house 1 that is experiencing less subsidence continues to subside, resulting in a gradual and automatic repair process.

[0036] The first project involved constructing a road in a rice paddy on an adjacent plot of land where 10 meters of soft, cohesive soil had accumulated. This involved adding a 1-meter embankment, and then constructing a paved road.

[0037] Upon completion of the road, monitoring steel pipes 4 were installed at two locations on the east side of House 1, at positions E and F for inclination measurement. Twelve months later, measurements were taken and found that the inclination in the direction of the road was 0.057 degrees and 0.069 degrees, respectively.

[0038] Next, displacement measurements were taken at four locations: house displacement measurement points A14, B15, C16, and D17. The results of the measurements taken 12 months later showed that existing house 1, located on the west side of the new road, had experienced differential settlement of 3 cm towards the road in one year, resulting in a house tilt of 3 / 1000.

[0039] Therefore, after examining the future progression of settlement, it was calculated that differential settlement will continue for more than a year, with a further differential settlement of 3 cm occurring.

[0040] As a countermeasure, a diaphragm wall was constructed on the east side of House 1, near the property boundary, using φ100mm steel pipes 4 at 0.5m intervals, extending across the width of the house and down to the lower ground level of the clay layer 6 that was settling. Subsequent measurements of differential settlement showed that the settlement had stopped, and House 1 gradually began to move in a direction that would repair itself. After 26 months, it was almost level and restored to a state where it did not cause any inconvenience to daily life.

[0041] Based on these results, it appears that differential settlement occurred in this case due to roads, embankment construction, and traffic vibrations. However, if, for example, a house 10 is built close to the adjacent property, differential settlement may occur as if being pulled towards it. To prevent this, a continuous wall of steel pipes 4 can be constructed near the boundary.

[0042] In this case, traffic vibrations occurred between the embankment and the road, and these vibrations were transmitted as a load, so it is thought that House 1 settled differentially in that direction. However, even in this case, differential settlement could be controlled by constructing an underground wall near the boundary.

[0043] It should be noted that the present invention is not limited to the above embodiments and can be modified in various ways. For example, the steel pipe is not limited to a round shape; square pipes or polygonal pipes can also be used. Furthermore, when constructing a new house, if it is anticipated that houses, roads, or embankments will be built nearby after construction, implementing the present invention will make it possible to prevent differential settlement after the new house is built. Additionally, a portion of the iron pipe can be driven down to the groundwater vein and used as a well to draw up water. [Brief explanation of the drawing]

[0044] [Figure 1] A cross-sectional view showing a steel pipe driven into the ground near the boundary with the adjacent property. [Figure 2] A floor plan showing the relationship between the site and the adjacent property. [Figure 3] A plan view showing steel pipes driven into the ground near the boundary with the adjacent property. [Figure 4] A plan view showing the installation of steel pipes when buried pipes are present. [Figure 5]A cross-sectional view showing differential settlement in the direction of the adjacent house. [Figure 6] A cross-sectional view showing the changes before (1) and after (2) the installation of steel pipes to control differential settlement. [Figure 7] A cross-sectional view showing the inclination of a cast steel pipe. [Figure 8] Example (1) [Figure 9] Example (2) [Explanation of Symbols]

[0045] 1. Housing 2 GL 3 Boundary lines 4 Steel pipe 5 Block wall 6. Clay layer 7. Underground stress range 8. Stress concentration areas 9. Buried pipes 10 adjacent houses 11 consecutive walls 12 inclinometer 13 support layer Displacement measurement point A of 14 houses Displacement measurement point B of 15 houses Displacement measurement point C of 16 houses Displacement measurement point D of 17 houses 18 Steel pipe inclination measurement position E 19. Measurement position F for the inclination of the steel pipe.

Claims

1. This differential settlement control method is designed to address differential settlement caused by earthquakes affecting the land and ground of existing houses, as well as by constantly changing surrounding environments and traffic vibrations. It is characterized by laying steel pipes in a continuous wall-like fashion within the site in the direction of settlement.

2. The differential settlement control method according to claim 1, characterized in that, in response to differential settlement due to insufficient bearing capacity or consolidation settlement of the ground of the existing house, steel pipes are laid in a continuous wall-like manner on the site in the direction of settlement.

3. The differential settlement control method according to claims 1 and 2, characterized in that the density of the continuous wall-shaped steel pipes is adjusted according to the weight and distance of surrounding structures such as houses and roads.

4. The differential settlement control method according to claims 1 to 3, characterized in that when the aforementioned wall-shaped steel pipes intersect with sewer pipes, rainwater pipes, water pipes, lighting pipes, or tree roots, the portion in which they intersect is left open during casting.

5. The differential settlement control method is characterized by laying steel pipes in a continuous wall-like manner within the site, taking into account the influence of adjacent houses, structures, and roads, in a newly constructed house where the house is built using columnar piles, surface improvement, or no improvement.

6. The differential settlement control method according to claims 1 to 5, characterized in that the aforementioned wall-like steel pipes reach a firm supporting layer or a non-liquefiable layer in the residential ground.

7. The differential settlement control method according to claims 1 to 6, characterized in that it monitors the inclination and settlement amount of each steel pipe to derive the stress acting on the ground and reflects this in the control of differential settlement.

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